But exactly how big the risks have been less clear. Randomized clinical trials are ruled out for ethical reasons and observational studies need a very large population base to quantify the relatively rare events. An international research group, led by Karolinska Institutet, has now compiled register data from the five Nordic countries on more than 4.

5 million pregnancies between 1997 and 2017. Among these were over 35,000 pregnancies where the mother had epilepsy. This is a uniquely large dataset that has enabled us to look at very unusual outcomes.

" Neda Razaz, first author, associate professor of epidemiology and researcher at the Department of Medicine, Solna, Karolinska Institutet She continues: "The main findings are that women with epilepsy are four times more likely to die during pregnancy and that during the first 42 days after delivery, the children of women with epilepsy have a 50 percent higher risk of illness or death." However, she points out that although the relative risk figures are high, the absolute numbers are small and the vast majority of pregnancies for women with epilepsy go well. For example, the fourfold increased risk of death in the pregnant woman means that the risk rises from five deaths per 100 000 pregnancies to 23 deaths per 100 000 pregnancies.

"96 percent of all women with epilepsy in our study had a completely uncomplicated pregnancy with a normal outcome. I don't want our results to scare women away from having children," says Neda Razaz. .